It is known in the art to improve the dye acceptability of acrylonitrile polymers by interpolymerizing them with a minor amount of p-acrylamidobenzoic acid or an alkali metal salt thereof, the acid and salt having the general formula: ##STR1## wherein R is hydrogen or methyl and M is hydrogen or an alkali metal.
As stated in U.S. Pat. No. 3,344,127, the acid monomer is present in an amount ranging from about 0.25% to about 10% and preferably from about 0.3% to about 4% based on the total monomer weight. The process proceeds via a free radical polymerization which can occur in numerous environments including an aqueous emulsion and yields a copolymer which can be utilized to provide fibers, films and filaments.
U.S. Pat. No. 3,344,127 makes clear, however, that the end polymers are primarily composed of acrylonitrile with the minor amount of p-acrylamidobenzoic acid being added to improve the dye acceptability of the polymer. The patent does not disclose or suggest that polymers composed of substantially pure p-acrylamidobenzoic acid could be produced.
It is also known in the art to prepare a related polymer derived from p-methacryloyloxybenzoic acid. This polymer essentially differs from the polymers of the present invention by having an oxygen group in place of the amino group. The manner of preparing the polymethacryloyloxybenzoic acid involves the reaction of the monomer in either dimethylformamide or cetyloxybenzoic acid. See Amerik et al, "Polymerization of p-Methacryloyloxybenzoic Acid in Mesomorphic and in Liquid States", J. Poly Sci., Part C, No. 23 pp. 231-238 (1968); Blumstein et al, "Polymerization of p-Methacryloyloxy Benzoic Acid With Liquid Crystalline Media", in Liquid Crystals 3, Part II, pp. 1075-1087 (Brown & Labes, Ed., Gordon and Breach Science Publishers Inc., New York, N.Y., 1971); Blumstein et al, "Crystallinity and Order in Atactic Poly (acryloyloxybenzoic acid) and Poly (methacryloyloxybenzoic acid)," Macromolecules, Vol. 9, No. 2, pp. 243-247 (March - April 1976); and Blumstein et al, "Oriented Polymer Growth in Thermotropic Mesophases", Macromolecules, Vol. 8, No. 1, pp. 73-76, (1975).
In commonly assigned United States Ser. No. 871,282 filed concurrently herewith by Eui Won Choe, and entitled "Ultra-High Molecular Weight Polymethacryloyloxybenzoic Acid and Method of Preparation", there is described a polymer and a process for preparing the polymer which primarily differs from the polymer of the present invention by having an oxy group in lieu of the amino group.
In commonly assigned United States Ser. No. 871,281 filed concurrently herewith by Eui Won Choe, Marshall Tan and Robert Mark Mininni, and entitled "Process for Producing Anisotropic Dopes and Articles Thereof from Benzoic Acid Derivative Polymers" there is described a method for preparing anisotropic dopes. These dopes may be employed in the formation of fibers. The anisotropic dopes per se are also described.
It is therefore an object of this invention to provide a novel polymer prepared from substantially pure p-acrylamidobenzoic acid or p-methacrylamidobenzoic acid (hereafter referred to as acryloylaminobenzoic acid and methacryloylaminobenzoic acid, respectively).
It is another object of this invention to prepare a novel polymer which is capable of forming an anisotropic melt.
It is yet another object of this invention to provide a novel polymer which can be formulated into an aqueous anisotropic spinning dope suitable for fiber formation.
It is a further object of this invention to provide a novel process for preparing a polymer from acryloylaminobenzoic acid or methacryloylaminobenzoic acid which involves a free radical polymerization of the monomer in an aqueous environment at relatively low temperatures.
These and other objects, as well as the scope, nature and utilization of the invention will be apparent from the following summary and detailed description of the invention.